Changed the starter in my focus tdci this afternoon been starting and driving find until about an hour ago I started it and the starter motor stayed engaged? Turned car off starters still trying tonturn the car over, I gave it a few taps with a hammer and herd it release then turned ignition off and it work fine

Question is, is this just a dodgy starter motor or is it a problem with ignition switch, I'll take the motor back just to be on the safe side I think

Didn't buy cheap either I went for a REMY (delco)